Voltage-regulating apparatus



Nov. 30, 1926.

H. A. THOMPSON VOLTAGE} REGULATING APPARATUS Filed Feb. 15, 1925INVENTORY l -Patented Nov. 3Q, 1926. g

UNITED STATES- 'HOWABD A. THOMPSON,

or wrnxmsnunc;

PENNSYLVANIA, ASSIGNOR TO THE UNION I SWITCH & SIGNAL COMPANY, OFSWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

'VOLTAGE-REGULATING APPARATUS. I

Application filed February My invention relates to voltage regulatingapparatus, that is, to apparatus for supplying a substantially constantvoltage toa-n electro-responsive device from a source of alternatingcurrent the voltage of which 'varies. a

.1 W111 descrlbeone form'and arrangement ofapparatus embodying myinvention, and

of a stretch of railway will then point out the novel features thereofin claims.

' interposed in the two track rails.

The sect onAA-B is provided with trackway circuits intended forco-operation with train carried govermng'means responsive to thepresence? of alternating current in the track rails. Since suchgoverning apparatus is usually controlled by the trackway currentsthrough the medium of suitable receiving apparatus carried on the trainin advance it follows that meansof the forward axle, and since trainsproceed in both directions over sect-ion A-B, must be provided forsupplying the track section with alternating 7 current at each end ofthe section. I accordhand and right hand ends,

' the section and each having rail 1 of the associated section A-B inthe the section with two track and T located at the left respectively,of

a secondary 4. constantly connected across the rails at the adjacent endof the section. 11 impedance 3 is interposed between the secondary 4 ofeach track transformer and one ingly provide transformers T winding Iusual manner.

The supply of alternating current to the two track transformers-T and Tis controlled by an auxiliary relay S controlled by means forming nopart of the present invention and "omitted from the drawing for the sakeof simplicity. This relay is so controlled that the relay is normallydeenergized, but is energized when a train moving from ri ht to leftenters section A-B and is retaine in the energized condition as long Fas the train occupies current not shown 'the rails adjacent 11 is asecond leg 13, 1925. Serial No. 8,918.

the section. As shown in the drawing, relay S is de-energized and underthese conditions transformer T is deenergized but transformer T isenergized, its primary winding 5 bein connected, over back contact 6-8of relay with terminals J and-K of a suitablesource of alternating inthe drawing. en relay S is energized, transformer T is deenergized buttransformer T is then sn 4 plied with current from terminals J and Cover front contact 6-7 of relay S. It will thus be plain cupied by atrain-moving from left to right or is unoccupied, alternating current issupplied to the section from transformer T but that when the section isoccupied .by a train moving from right to left the current is suppliedto the rails by transformer T. 7

Section A-B is further provided with a track relay R arranged to receiveenergy from the track rails at a point adjacent transformer T. Due tothe impedance of the track rails, and to the leakage through the trackballast, the difference of potential 'between the rails of the sectionA-B at point A will be considerably greater when the section is beingsupplied with alternating current from transformer T than whentransformer T is supplying the current to the section. In the absence ofany preventative means this widely varying difference of potential wouldbe applied to the of the relay and might damage i This condition isundesirable and I therefore provide a regulating transformer D tomaintain substantially constant-the voltage applied to the relayirrespective of ence of potential between rails at point A. Thistransformer D comprises a continuous magnetizable core 9'havmg a firstleg 11 carrying a primary as desi tioned that for normal va e andproporues of potential terminals that when section A-B is 00-alternating v variations in the difierwinding 15 connected acrosspointA. Opposite to leg s difference between rails at point A, that is,

when transformer T is energized, the leg 10 ismagnetically saturated.The transformer D also comprises a magnetic leakage member 12 ofmagnetic material which member 7 forms a shunt around leg 11 of core 9.The member 12 is separated from the core 9 by two air gaps 1 3 and '13and carries a secwinding 14 is opposed to ondary winding 14. A portion'of the flux created by winding 15 threads"winding '14 and inducestherein an electromotive force. Secondary winding 14 is connected inseries with relay R, and the relay and winding 14 are in turn connectedacross winding 15 in such manner that the voltage induced in the voltageapplied towinding 15 from the track rails.

he parts are so proportioned that when section A-B is supplied withalternating current from transformer T the voltage across relay R isofthe proper value for operating relay R and the magnetic flux in core 9is of such value that leg 10 is saturated. Then if the voltage acrossthe rails at point A increases, as by the energization of transformer T,the increased potential difierence between the rails at point A causesan increase in the current through winding 15 which results in anincreased flux through leg 11. Leg 10 is, however, saturated and so thelarger part of the additional flux threads through member 12 thusincreasing the voltage induced in winding 14. Since this voltage opposesthe voltage supplied from the rails, the result is that the increase indifference of potential eflective at the terminals of the relay is lessthan the actual increase in the'difi'erence of potential between ra1 s.

The ratio of turns in windings l5 and 14 is so chosen that a givenincrease in voltage applied to winding 15 causes an equal increase inthe voltage induced in winding 14. With this arrangement it is plainthat the voltage applied to the terminals of relay R is substantiallyconstant over a wide range of variation in the potential differencebetween rails.

The relay B may be used to control apparatus not shown in the drawing,such as a trackway signal, in any desired manner.

I do-not in the present case, make any claim for the combination of thetransformer D with the track rails and track relay of a ra' waysignaling system, such invention bein claimed in my co-pendingapplication filed on the 15th day of August, 1924, Serial No. 732,196,for railway traific controlling apparatus.

I clalm is:

Although I have herein shown and de-- scribed only one form and,arrangement of apparatus embodying my invention, it is understood thatvarious changes and modifications may be made therein within thevention.

Having thus described my invention, what 1. In combination, a source ofalternating current having 'a'variable voltage, an electroresponsivedevice supplied with current from said source, a continuous magnetizablecore having a first leg carrying a primary winding connected in parallelwith said de vice, and having a second leg that is magneticallysaturated when the voltage of said source is at normal value, amagnetizable leakage member shunting said first leg, and

a secondary winding on said member and connected in series with saiddevice in such manner that the voltage induced in said secondary isopposed to the potential applied to the device from the source.

2. In combination, a source of alteriiating current having a variablevoltage, an electro-responsive device supplied with currentfrom saidsource, a transformer comprising a core having a first leg carrying aprimary winding connected in parallel with said device and having asecond leg that is mag- 'netically saturated at normal value of thevoltage of said source, a magnetic leakage member shunting said firstleg, and a secondary winding on said member series with said device.

3. Voltage regulating apparatus comprising a magnetizable core carryinga primary winding and having a leg which is saturated at the normalvoltage applied to said priconnected in mary winding, a magnetic leakagemember shunting the part of sald core which carries the primary winding,and a secondary winding on said leakage member connected with saidprimary winding but so wound that the 4 voltage induced therein bycurrent in the primary winding opposes the voltage applied to theprimary winding.

In testimony whereof I affix my signature.

HOWARD A. THOMPSON.

